The structural, magnetic and electronic properties of 2D VX2 (X = S, Se) monolayers and graphene/VX2 heterostructures were studied using a DFT+U approach. It was found that the stability of the 1T phasesof VX2 monolayers is linked to strong electron correlation effects. The study of vertical junctions comprising of graphene and VX2 monolayers demonstrated that interlayer interactions lead to theformation of strong spin polarization of both graphene and VX2 fragments while preserving the linear dispersion of graphene-originated bands. It was found that the insertion of Mo atoms between thelayers leads to n-doping of graphene with a selective transformation of graphene bands keeping the spin-down Dirac cone intact.